Composite heat insulation pad, battery and electric device

Abstract

The utility model relates to a composite heat insulation pad, a battery and an electric device. The composite heat insulation pad comprises a phase change heat insulation layer and a heat absorption expansion layer, the phase change heat insulation layer comprises a heat insulation base material and a phase change material filled in pores of the heat insulation base material, and the heat absorption expansion layer is arranged on at least one side of the peripheral side of the phase change heat insulation layer and / or in the phase change heat insulation layer. According to the composite heat insulation pad, on one hand, the heat insulation base material in the phase change heat insulation layer can play a role in heat insulation, the phase change material in the phase change heat insulation layer can play a role in phase change heat absorption and cooling, on the other hand, the heat absorption expansion layer arranged on at least one side and / or in the phase change heat insulation layer absorbs a large amount of heat, the size of the heat absorption expansion layer is obviously changed, and the heat absorption effect is improved. For example, when the composite heat insulation pad is arranged between the battery monomers, the battery monomers can be jacked open, and the distance between the adjacent battery monomers is increased, so that the problem of thermal runaway caused by excessive concentration of heat is prevented or delayed, and the service life of the battery is further prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a composite thermal insulation pad, a battery and an electrical device. Background Art

[0002] With the development of new energy technologies, batteries are increasingly used in the market. People's requirements for battery performance, such as energy density, are also getting higher and higher. However, battery cells with higher energy density have greater residual energy after thermal runaway. When a battery cell thermally runs away, its heat will continue to transfer from the battery cell to the adjacent battery cells, thereby causing heat diffusion of the entire battery and causing damage to the entire battery. Therefore, how to prevent or delay battery thermal runaway is an urgent problem to be solved. Utility Model Content

[0003] Based on this, it is necessary to provide a composite thermal insulation pad, battery and electrical device to prevent or delay the problem of battery thermal runaway.

[0004] In a first aspect, the present application provides a method comprising:

[0005] A phase-change heat-insulating layer, comprising a heat-insulating substrate and a phase-change material filled in pores of the heat-insulating substrate; and

[0006] The heat-absorbing expansion layer is arranged on at least one side of the outer peripheral side of the phase-change heat-insulating layer and / or inside the phase-change heat-insulating layer.

[0007] The composite thermal insulation pad mentioned above in the present application, on the one hand, the thermal insulation substrate in the phase change thermal insulation layer can play a role of thermal insulation, and the phase change material therein can play a role of phase change heat absorption and cooling, and on the other hand, the heat absorption expansion layer arranged on at least one side and / or inside the phase change thermal insulation layer absorbs a large amount of heat, and the heat absorption expansion layer decomposes when heated to produce a large amount of gas. The gas generates a large thrust, so that the interlayers are subjected to the thrust and expand outward, thereby causing the heat absorption expansion layer to undergo a significant volume change. For example, when the composite thermal insulation pad is arranged between battery cells, the battery cells can be pushed open, and the distance between adjacent battery cells can be increased, thereby preventing or delaying the problem of thermal runaway caused by excessive heat concentration, thereby improving the service life of the battery.

[0008] In some embodiments, the heat-absorbing expansion layer is provided inside the heat-insulating substrate. In this way, the heat is first insulated by the heat-insulating substrate and then reaches the heat-absorbing expansion layer, which is conducive to giving full play to the heat-insulating performance of the composite heat-insulating pad.

[0009] In some embodiments, the projection of the heat-absorbing expansion layer on the thermal insulation substrate in the thickness direction of the composite thermal insulation pad does not exceed the thermal insulation substrate. In this way, the edge of the heat-absorbing expansion layer does not exceed the thermal insulation substrate in the thickness direction of the composite thermal insulation pad, so that the heat can be insulated by the thermal insulation substrate first and then reach the heat-absorbing expansion layer, which is conducive to giving full play to the thermal insulation performance of the composite thermal insulation pad.

[0010] In some embodiments, a projected area of ​​the heat-absorbing expansion layer on the thermal insulation substrate in the thickness direction of the composite thermal insulation pad is 90% to 100% of the area of ​​the thermal insulation substrate.

[0011] In some embodiments, the composite thermal insulation pad also includes a first outer thermal insulation layer, which is arranged on at least one side of the outer peripheral side of the phase change thermal insulation layer in the thickness direction. In this way, the first outer thermal insulation layer first plays a heat insulation role, and then the heat is transferred to the phase change thermal insulation layer, which is insulated by the thermal insulation substrate and absorbed by the phase change material therein, and then the heat continues to transfer to the heat absorption expansion layer to be absorbed by it and expand due to heat. When the composite thermal insulation pad is arranged between battery cells, the battery cells can be pushed open, and the distance between adjacent battery cells can be increased, thereby preventing or delaying the problem of thermal runaway caused by excessive heat concentration, thereby improving the service life of the battery.

[0012] In some embodiments, there are at least two heat-absorbing expansion layers, and at least one heat-absorbing expansion layer is provided on both sides of the outer peripheral side of the phase-change heat-insulating layer in the thickness direction. In this way, the heat-absorbing expansion layer and the phase-change heat-insulating layer in the middle can both absorb and insulate heat, and the heat-absorbing expansion layer on the outside can also decompose and expand under heat, preventing or delaying the problem of thermal runaway caused by heat concentration, thereby improving the service life of the battery.

[0013] In some embodiments, the composite thermal insulation pad further includes a second outer thermal insulation layer, which is disposed on the side of the heat-absorbing and expansion layer away from the phase-change thermal insulation layer. In this way, the heat first passes through the insulation and heat-absorbing cooling of the second outer thermal insulation layer and the phase-change thermal insulation layer on both sides of the composite thermal insulation pad, and then reaches the heat-absorbing and expansion layer to be absorbed. When the heat absorbed by the heat-absorbing and expansion layer causes it to decompose and expand due to the heat, it can push open the adjacent insulation objects such as battery cells, thereby preventing or delaying the heat concentration from causing thermal runaway.

[0014] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0015] (1) The heat-absorbing and expanding layer is an expanded graphite layer;

[0016] (2) The thermal insulation substrate is a ceramic material thermal insulation substrate.

[0017] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0018] (1) The thickness of the heat-absorbing expansion layer is 0.5 mm to 5 mm;

[0019] (2) The thickness of the phase change thermal insulation layer is 0.5 mm to 5 mm.

[0020] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0021] (1) The composite thermal insulation pad further includes a first packaging layer, which is disposed on the outer surface of the heat absorption and expansion layer and packages the heat absorption and expansion layer;

[0022] (2) The composite thermal insulation pad also includes a second encapsulation layer, which is arranged on the outer surface of the phase change thermal insulation layer and encapsulates the phase change thermal insulation layer.

[0023] In some embodiments, the composite thermal insulation pad satisfies at least one of the following conditions:

[0024] (1) The first packaging layer is an aluminum-plastic film or a polymer packaging film;

[0025] (2) The second packaging layer is an aluminum-plastic film or a polymer packaging film;

[0026] (3) The thickness of the first encapsulation layer is 0.1 mm to 0.3 mm;

[0027] (4) The thickness of the second packaging layer is 0.1 mm to 0.3 mm.

[0028] In some embodiments, the composite thermal insulation pad further includes a first packaging frame and a second packaging frame, and the first packaging frame cooperates with the second packaging frame to fix the phase change thermal insulation layer and the heat absorption expansion layer.

[0029] In a second aspect, the present application provides a battery comprising the composite thermal insulation pad provided in the first aspect of the present application.

[0030] In some embodiments, the battery further includes a plurality of battery cells, and the composite thermal insulation pad is disposed between at least two adjacent battery cells.

[0031] In some embodiments, the composite thermal insulation pad is disposed between large surfaces of at least two adjacent battery cells.

[0032] In a third aspect, the present application provides an electrical device, comprising the battery provided in the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to one embodiment of the present application;

[0034] Figure 2 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0035] Figure 3 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0036] Figure 4 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0037] Figure 5 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0038] Figure 6 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0039] Figure 7 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0040] Figure 8 This is a schematic diagram of the cross-sectional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0041] Fig. 9 This is a schematic diagram of the three-dimensional structure of a composite thermal insulation pad according to another embodiment of the present application;

[0042] Fig.10 A schematic diagram of the structure of a battery according to one embodiment of the present application;

[0043] Fig.11 This is a schematic diagram of the exploded structure of a battery according to one embodiment of the present application;

[0044] Fig.12 is a schematic structural diagram of a battery cell in a battery according to an embodiment;

[0045] Fig.13 A schematic diagram of an electrical device using a battery as a power source according to an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 10. Composite thermal insulation pad; 11. Phase change thermal insulation layer; 111. First sub-phase change thermal insulation layer; 112. Second sub-phase change thermal insulation layer; 12. Heat absorption expansion layer; 131. First outer thermal insulation layer; 132. Second outer thermal insulation layer; 141. First encapsulation layer; 142. Second encapsulation layer; 151. First bonding layer; 142. Second bonding layer; 161. First encapsulation frame; 162. Second encapsulation frame;

[0048] 20. Battery cell; 21. Housing; 22. Electrode assembly; 23. Cover plate;

[0049] 30. Battery;

[0050] 40. Electrical equipment. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0052] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0053] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0055] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0056] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0057] At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries, especially power batteries, are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0058] A battery cell is the smallest unit that makes up a battery. A battery may include one or more battery cells, and multiple battery cells may be connected in series, in parallel, or in a hybrid connection. Among them, a hybrid connection means that multiple battery cells are connected in both series and in parallel.

[0059] After multiple battery cells are connected to each other and arranged in a certain order, they can be directly placed in a box to assemble into a battery. Alternatively, multiple battery cells can be first assembled into a battery module, and then multiple battery modules are connected to each other to form a whole, and finally the whole battery module is placed in a box to form a battery.

[0060] In order to solve the above-mentioned battery thermal runaway problem and reduce the damage and risk to the entire battery.

[0061] See also Figure 1 or Figure 4 An embodiment of the present application provides a composite thermal insulation pad 10 , including a phase change thermal insulation layer 11 and a heat absorption expansion layer 12 .

[0062] The phase-change heat-insulating layer 11 includes a heat-insulating substrate and a phase-change material filled in pores of the heat-insulating substrate.

[0063] The heat-absorbing expansion layer 12 is disposed on at least one side of the outer periphery of the phase-change heat-insulating layer 11 (see Figure 4 ) and / or within the phase change insulation layer 11 (see Figure 1 ).

[0064] The composite thermal insulation pad 10 mentioned above in the present application, on the one hand, the thermal insulation substrate in the phase change thermal insulation layer 11 can play a role in thermal insulation, and the phase change material therein can play a role in phase change heat absorption and cooling, and on the other hand, the heat absorption expansion layer 12 arranged on at least one side and / or inside the phase change thermal insulation layer 11 absorbs a large amount of heat, and the heat absorption expansion layer 12 decomposes under heat to produce a large amount of gas, and the gas produces a large thrust, so that the interlayer is subjected to the thrust and expands outward, thereby causing the heat absorption expansion layer 12 to undergo a significant volume change. For example, when the composite thermal insulation pad 100 is arranged between battery cells, the battery cells can be pushed open, and the distance between adjacent battery cells can be increased, thereby preventing or delaying the problem of thermal runaway caused by excessive heat concentration, thereby improving the service life of the battery.

[0065] In some embodiments, the heat-absorbing expansion layer 12 includes but is not limited to a film layer that absorbs heat to expand physically and / or chemically, such as but not limited to an expanded graphite layer. The interlayer compound of the expanded graphite layer decomposes under heat to produce a large amount of gas, and the gas generates a large thrust, so that the interlayer is subjected to the thrust and expands outward, thereby causing the expanded graphite to undergo a significant volume change. Further, the heat-absorbing expansion layer 12 may be an expanded graphite layer. The volume expansion rate of expanded graphite is 140 to 310 times, and a significant reaction will occur at 400°C, resulting in a volume change.

[0066] It can be understood that the thermal insulation substrate has pores, and the phase change material can be filled in the pores of the thermal insulation substrate. In some embodiments, the thermal insulation substrate is a ceramic material thermal insulation substrate, such as ceramic fiber felt.

[0067] In the present application, "ceramic material" includes but is not limited to at least one of ceramic oxides, ceramic nitrides, and ceramic carbides. Among them, ceramic oxides include but are not limited to at least one of silicon oxide and aluminum oxide, ceramic nitrides include but are not limited to silicon nitride, and ceramic carbides include but are not limited to silicon carbide.

[0068] Furthermore, the ceramic fiber felt may be a silica aerogel ceramic felt. As an example, the silica aerogel ceramic felt may be prepared by inorganic fiber reinforcement technology to prepare aerogel materials, and is prepared by impregnation sol, gel, solvent replacement and supercritical drying processes. The ceramic fiber mat has ceramic fiber as the core skeleton, which can not only well infiltrate the liquid phase change material so that the phase change material is filled in the pores of its core skeleton, but also has low thermal conductivity, good high temperature resistance (1280°C), resistance to instantaneous thermal shock, flame retardant properties and mechanical properties, no powdering, and is flexible and resilient, and is compatible with the battery pack manufacturing process.

[0069] It is understood that the phase change insulation layer 11 can be obtained by soaking the porous insulation substrate such as ceramic fiber felt in a liquid phase change material, for example, soaking in a molten phase change material and then cooling it or soaking in a phase change material solution and then drying or heat-insulating it. In addition to absorbing heat, the phase change insulation layer 11 can also play a role in heat insulation.

[0070] Furthermore, the phase change material may be a solid, liquid or semi-solid phase change material. Optionally, the materials of the phase change material include but are not limited to crystalline hydrated salts, phase change molten salts, paraffin, silicone oil, silica sol, aluminum sol, silica aluminum sol, fatty acids, alcohols and other substances that can undergo phase change and absorb heat, and its application range is wider, so it can provide better thermal insulation performance. Further, the crystalline hydrated salt includes but is not limited to at least one of the crystalline hydrated salts of sodium carbonate and calcium chloride, such as at least one of sodium carbonate decahydrate (Na2CO3·10H2O) and calcium chloride hexahydrate (CaCl2·6H2O). Aluminum sol includes aluminum hydroxide sol.

[0071] In some embodiments, the thickness of the heat-absorbing and expanding layer 12 is 0.5 mm to 5 mm. As an example, the thickness can be 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, or 5.0 mm.

[0072] In some embodiments, the thickness of the phase change insulation layer 11 is 0.5 mm to 5 mm. As an example, the thickness can be 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, or 5.0 mm.

[0073] See also Figure 1 and Figure 2 In some embodiments, a heat absorbing expansion layer 12 is provided inside the phase change insulation layer 11; further, a heat absorbing expansion layer 12 is provided inside the insulation substrate. In this way, the heat first passes through the insulation substrate of the phase change insulation layer 11, and then reaches the heat absorbing expansion layer 12, which is conducive to giving full play to the insulation performance of the composite insulation pad 10.

[0074] Specifically, see Figure 1 A groove for placing the heat absorbing expansion layer 12 can be provided inside the heat insulating substrate of the phase change heat insulating layer 11. Figure 2 The phase-change insulation layer 11 may also be provided with multiple layers, for example, the phase-change insulation layer 11 includes at least two sub-phase-change insulation layers, and the heat-absorbing expansion layer 12 is provided between at least two adjacent sub-phase-change insulation layers; specifically, the composite insulation pad 10 includes a first sub-phase-change insulation layer 111, a heat-absorbing expansion layer 12, and a second sub-phase-change insulation layer 112 which are stacked in sequence. Each sub-phase-change insulation layer also includes a heat-insulating substrate and a phase-change material filled in the pores of the heat-insulating substrate.

[0075] Furthermore, the projection of the heat-absorbing expansion layer 12 on the heat-insulating substrate in the thickness direction of the composite heat-insulating pad 10 does not exceed the heat-insulating substrate. In this way, the edge of the heat-absorbing expansion layer 12 does not exceed the heat-insulating substrate in the thickness direction of the composite heat-insulating pad 10, so that the heat can first pass through the heat-insulating substrate for insulation, and then reach the heat-absorbing expansion layer 12, which is conducive to giving full play to the heat-insulating performance of the composite heat-insulating pad 10.

[0076] Furthermore, the projected area of ​​the heat-absorbing expansion layer 12 on the insulation substrate in the thickness direction of the composite insulation pad 10 is 90% to 100% of the area of ​​the insulation substrate. For example, it can be 90%, 95%, 96%, 98%, or 100%.

[0077] See also Figure 3 Furthermore, the composite thermal insulation pad 10 may also include a first outer thermal insulation layer 131, which is disposed on at least one side of the outer peripheral side of the phase change thermal insulation layer 11 along the thickness direction. In other words, along the thickness direction, the first outer thermal insulation layer 131 is disposed on at least one side of the outer peripheral side of the phase change thermal insulation layer 11.

[0078] Furthermore, first outer insulation layers 131 are provided on both sides of the outer peripheral side of the phase-change insulation layer 11 in the thickness direction. In this way, the first outer insulation layer 131 first acts as an insulation layer, and then the heat is transferred to the phase-change insulation layer 11, where it is insulated by the insulation substrate and the phase-change material absorbs the heat, and then the heat is further transferred to the heat-absorbing expansion layer 12 where it is absorbed and expands due to heat. When the composite insulation pad 100 is provided between battery cells, the battery cells can be pushed open, and the spacing between adjacent battery cells can be increased, thereby preventing or delaying the problem of thermal runaway caused by excessive heat concentration, thereby improving the service life of the battery.

[0079] See also Figure 4 In some other embodiments, a heat absorbing expansion layer 12 is provided on at least one side of the outer peripheral side of the phase change insulation layer 11. The heat absorbing expansion layer 12 is provided on at least one side of the outer peripheral side of the phase change insulation layer 11 along the thickness direction.

[0080] It can be understood that, in some embodiments, the above-mentioned heat absorption expansion layer 12 is provided on at least one side of the outer periphery of the phase change thermal insulation layer 11 and inside the phase change thermal insulation layer 11 .

[0081] Furthermore, there are at least two heat-absorbing expansion layers 12, and at least one heat-absorbing expansion layer 12 is provided on both sides of the outer peripheral side of the phase-change insulation layer 11 in the thickness direction. In other words, the composite insulation pad 10 includes a heat-absorbing expansion layer 12, a phase-change insulation layer 11, and a heat-absorbing expansion layer 12 stacked in sequence. In this way, the heat-absorbing expansion layer 12 and the phase-change insulation layer 11 in the middle can both absorb and insulate heat, and the heat-absorbing expansion layer 12 on the outside can also decompose and expand under heat, preventing or delaying the problem of thermal runaway caused by heat concentration, thereby improving the service life of the battery.

[0082] See also Figure 5 Furthermore, the composite thermal insulation pad 10 may also include a second outer thermal insulation layer 132, which is disposed on the side of the heat absorption expansion layer 12 away from the phase change thermal insulation layer 11. In other words, the composite thermal insulation pad 10 includes the second outer thermal insulation layer 132, the heat absorption expansion layer 12, and the phase change thermal insulation layer 11 stacked in sequence. In this way, the heat first passes through the insulation and heat absorption cooling of the second outer thermal insulation layer 132 and the phase change thermal insulation layer 11 on both sides of the composite thermal insulation pad 10, and then reaches the heat absorption expansion layer 12 to be absorbed. When the heat absorbed by the heat absorption expansion layer 12 causes it to decompose and expand due to heat, it can push open the adjacent insulation objects such as battery cells, and prevent or delay the thermal runaway caused by heat concentration.

[0083] Furthermore, there are at least two second outer heat insulation layers 132 and heat absorption expansion layers 12, which are respectively arranged on the side of the two heat absorption expansion layers 12 away from the phase change heat insulation layer 11. In other words, the composite heat insulation pad 10 includes the second outer heat insulation layer 132, the heat absorption expansion layer 12, the phase change heat insulation layer 11, the heat absorption expansion layer 12 and the first outer heat insulation layer 131 (such as Figure 5 as shown).

[0084] Furthermore, the material selection range of each of the above-mentioned outer insulation layers can be the same as that of the insulation substrate, for example, it can be a ceramic material insulation layer, including but not limited to ceramic fiber felt, and can also be an insulation coating. It can be understood that the insulation coating can be directly formed on the surface of the heat absorption expansion layer 12 in the form of slurry coating. The ceramic fiber felt can be formed at the corresponding position by bonding with a bonding layer. Ceramic fiber felt and thermal insulation coating can be selected as needed or used in combination. In comparison, the thickness of the insulation coating is thinner, the overall thickness of the prepared composite insulation pad is thinner, and the required space is relatively smaller. Ceramic fiber felt has better strength, such as compression performance, and can also be convenient for processing such as opening grooves. The insulation layer of the composite insulation pad 10 can optionally adopt an insulation coating, or a composite of the insulation coating and ceramic fiber felt, which can take into account both smaller occupied space and better insulation performance.

[0085] In some embodiments, the above-mentioned thermal insulation substrate and the outer thermal insulation layer independently meet the following conditions: thermal conductivity at 25°C ≤ 0.020W / m·K, thermal conductivity at 200°C ≤ 0.027W / m·K, thermal conductivity at 300°C ≤ 0.035W / m·K, and thermal conductivity at 500°C ≤ 0.080W / m·K. The test steps of thermal conductivity are as follows: cut the sample into a size of 300mm*300mm, stack it to a thickness that meets the minimum thickness requirement of 6mm for the test; put the sample into a thermal conductivity meter, set different temperatures, and measure the thermal conductivity of the sample at different temperatures.

[0086] In some embodiments, the density of the thermal insulation substrate and the outer thermal insulation layer is independently 0.2 g / cm 3 ~0.22g / cm 3 .

[0087] See also Figures 6 to 8 In some embodiments, the composite thermal insulation pad 10 may further include a first packaging layer 141. The first packaging layer 141 is disposed on the outer surface of the heat absorption expansion layer 12 and encapsulates the heat absorption expansion layer 12. In this way, the heat absorption expansion layer 12 is individually encapsulated by the first packaging layer 141 and then combined with other film layers, which can protect the heat absorption expansion layer 12. At the same time, when the heat absorption expansion layer 12 is not heated enough to break through the first packaging layer 141, the material of the heat absorption expansion layer 12 or the generated gas will not escape, so that the heat absorption effect can be achieved. When the heat absorption expansion layer 12 breaks through the first packaging layer 141 due to heat, a significant volume change occurs at this time, which plays a role in pushing open the battery cell, preventing or delaying the heat concentration that leads to thermal runaway.

[0088] Please continue reading Figures 6 to 8In some embodiments, the composite thermal insulation pad may further include a second encapsulation layer 142. The second encapsulation layer 142 is disposed on the outer surface of the phase change insulation layer 11 and encapsulates the phase change insulation layer 11. By encapsulating the phase change insulation layer 11 through the second encapsulation layer 142, the phase change insulation layer 11 can be protected. In particular, since the phase change material of the phase change insulation layer 11 will undergo a phase change, for example, a solid phase change material at room temperature will turn into a liquid state after absorbing heat, the second encapsulation layer 142 can also serve to isolate the phase change material in a liquid state from the outside. In addition, some preparation processes inevitably cause the phase change material to carry moisture. The second encapsulation layer 142 is used to encapsulate the phase change insulation layer 11 to prevent moisture overflow from causing adverse effects on the battery. When the phase change material of the phase change insulation layer 11 absorbs heat and vaporizes to break the second encapsulation layer 142, that is, the encapsulation of the second encapsulation layer 142 fails, at which time the thermal insulation substrate in the phase change insulation layer 11 can continue to play an insulating role.

[0089] It can be understood that when a heat-absorbing expansion layer 12 is provided inside the phase-change heat-insulating layer 11 , the heat-absorbing expansion layer 12 located inside is also encapsulated in the second encapsulation layer 142 .

[0090] Please continue reading Figure 6 and Figure 7 It can be understood that when the heat-absorbing expansion layer 12 is provided inside the phase-change heat-insulating layer 11, the heat-absorbing expansion layer 12 is first encapsulated by the first encapsulating layer 141, and then the whole is provided inside the phase-change heat-insulating layer 11. Among them, the phase-change heat-insulating layer 11 is further encapsulated by the second encapsulating layer 142 as a whole.

[0091] Furthermore, in Figure 7 In a specific example, both sides of the outer peripheral side of the phase change heat insulation layer 11 along the thickness direction are bonded and fixed to the first outer heat insulation layer 131 by the first bonding layer 151 and the second bonding layer 152 respectively.

[0092] See also Figure 8 At least one side of the outer periphery of the phase change insulation layer 11 is provided with a heat absorption expansion layer 12, which is first encapsulated by the first encapsulation layer 141 and then stacked with the phase change insulation layer 11 as a whole. The phase change insulation layer 11 is further encapsulated by the second encapsulation layer 142 as a whole.

[0093] Further, in Figure 8 In a specific example, the composite thermal insulation pad 10 includes the above-mentioned heat absorption expansion layer 12, the phase change insulation layer 11 and the heat absorption expansion layer 12 which are stacked in sequence. The heat absorption expansion layer 12 is first encapsulated by the first encapsulation layer 141, and then stacked as a whole with the phase change insulation layer 11 encapsulated by the second encapsulation layer 142. For example, one side of the adhesive layer is bonded to the outside of the first encapsulation layer 141, and the other side of the adhesive layer is bonded to the second encapsulation layer 142 of the phase change insulation layer 11.

[0094] Furthermore, in some examples, at least part of the phase change material is directly filled in the pores of the thermal insulation substrate. In addition to the phase change material filled in the pores of the thermal insulation substrate, the phase change insulation layer 11 also includes a part of the phase change material located outside the thermal insulation substrate and encapsulated in the second encapsulation layer 142.

[0095] In other examples, the phase change material can also be filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. It is understandable that in the same thermal insulation substrate, two states of phase change materials can also be included at the same time, one is that the phase change material is directly filled in the pores of the thermal insulation substrate, and the other is that the phase change material is filled in the pores of the thermal insulation substrate in the form of phase change microcapsules. In other words, the pores of the thermal insulation substrate of the phase change insulation layer 11 can be filled with phase change microcapsules. The phase change microcapsules include a core material and a wall material, the wall material is wrapped around the outer surface of the core material, and the core material includes a phase change material. It is understandable that in some examples, the pores of the thermal insulation substrate can also be directly filled with phase change materials and filled with the above-mentioned phase change microcapsules at the same time.

[0096] The above-mentioned phase change insulation layer 11 can be obtained by dispersing phase change microcapsules in a solvent to obtain a phase change microcapsule dispersion, then immersing a thermal insulation substrate in the phase change microcapsule dispersion to fill the phase change microcapsules in the pores of the thermal insulation substrate, and removing the solvent in the phase change microcapsule dispersion.

[0097] In this way, the phase change microcapsules in the phase change insulation layer 11 absorb heat. When the battery cell thermally runs away, the phase change material in the adjacent composite insulation pad vaporizes and breaks the second packaging layer 142, that is, the second packaging layer 142 fails. At this time, the insulation substrate in the phase change insulation layer 11 can continue to play an insulation role.

[0098] Further, the wall material includes a polymer matrix and ceramic particles filled in the polymer matrix. Further, the mass ratio of the polymer matrix to the ceramic particles is 3:(7-11), and as an example, the mass ratio of the polymer matrix to the ceramic particles can be 3:7, 3:8, 3:9, 3:10, 3:11. By controlling the mass content of the ceramic particles in the wall material to be larger, the pressure resistance and heat insulation capacity of the wall material can be improved.

[0099] Furthermore, the mass ratio of the polymer matrix to the core material is 1:(1.3-1.6). As an example, the mass ratio of the polymer matrix to the core material can be 1:1.3, 1:1.4, 1:1.5, 1:1.6. This can further improve the pressure resistance of the phase change microcapsule.

[0100] Furthermore, the polymer matrix includes but is not limited to any one of phenolic resin, polyacrylonitrile resin, melamine formaldehyde resin, etc. The polymer matrix not only has good insulation, but also has good compatibility with phase change materials such as paraffin wax, can form a stable interface with the phase change material, and improve the thermal stability of the phase change microcapsules.

[0101] Furthermore, the Dv50 particle size of the phase change microcapsule is 5 μm to 8 μm. The Dv50 particle size is the volume average particle size Dv50, which indicates the particle size corresponding to when the cumulative volume distribution percentage of the particles reaches 50%, and can be tested by methods known in the art. For example, it can be measured using a laser particle size analyzer (such as Malvern Master Size 3000).

[0102] Furthermore, the thermal conductivity of the wall material at 25° C. is ≥ 0.32 W / m·K. Such a wall material has a good thermal conductivity and can better conduct heat to the phase change material inside it.

[0103] Furthermore, the melting point of the wall material is greater than 98° C. The wall material has a relatively high melting point, and can maintain the structural stability of the microcapsule within the phase change temperature range of the phase change material.

[0104] In some examples of the present application, the ceramic particles include but are not limited to at least one of boron nitride particles, silicon nitride particles, silicon carbide particles, silicon dioxide particles, etc. Further, the Dv50 of the ceramic particles is 60-90 nm. As an example, the Dv50 of the ceramic particles can be any value of 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 83 nm, 85 nm, 90 nm or between any two values. The silicon dioxide particles of the above-mentioned specific particle size are conducive to doping and uniform dispersion in the substrate.

[0105] Phase change microcapsules can be obtained by in-situ polymerization, where the wall material covers the core material. In some examples, the preparation method of phase change microcapsules includes the following steps: dispersing ceramic particles in water to form an aqueous phase; heating the phase change material to a molten state to form an oil phase; mixing the aqueous phase and the oil phase, stirring to form a Pickering emulsion, adding the raw materials required for preparing the polymer matrix of the wall material (such as water-soluble polymerization monomers or prepolymer aqueous solutions) to the Pickering emulsion, stirring and polymerizing at room temperature, and generating a non-water-soluble polycondensate (i.e., polymer matrix) with a cross-linked three-dimensional network structure at the interface of the emulsion.

[0106] The polymer matrix of the above material has better compatibility with phase change materials such as paraffin, and also facilitates the uniform dispersion of ceramic particles, thereby ensuring the stability of phase change microcapsules.

[0107] In some examples, each of the above-mentioned encapsulation layers can be formed by encapsulating two encapsulation films, for example, by encapsulating by edge pressing or edge wrapping, so an encapsulation margin is provided at the edge of each encapsulation layer. Further, the encapsulation margin is formed into an edge pressing structure by edge pressing, that is, the encapsulation margin is located between two adjacent film layers. It can be understood that one or more of the first encapsulation layer 141 and the second encapsulation layer 142 can be used at will.

[0108] Furthermore, the first packaging layer 141 is an aluminum-plastic film or a polymer packaging film.

[0109] Further, the second encapsulation layer 142 is an aluminum-plastic film or a polymer encapsulation film. Further, the second encapsulation layer 142 is an aluminum-plastic film. Because the aluminum-plastic film has better strength, it is used to encapsulate the phase change insulation layer 11 that undergoes phase change, and can play a better role in isolating the phase change insulation layer 11 from the outside.

[0110] Furthermore, the aluminum-plastic film includes a polypropylene layer, an aluminum layer and a nylon layer stacked from inside to outside.

[0111] Furthermore, the polymer packaging film may be a PET film (polyethylene terephthalate film) or a PI film (polyimide film).

[0112] Further, the thickness of the first encapsulation layer 141 is 0.1 mm to 0.3 mm; for example, it may be 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and may be 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0113] Furthermore, the thickness of the second packaging layer 142 is 0.1 mm to 0.3 mm; for example, it may be 0.1 mm, 0.15 mm, 0.2 mm, 0.3 mm, and may be 0.1 mm to 0.15 mm, or 0.2 mm to 0.3 mm.

[0114] In some embodiments, the composite thermal insulation pad 10 may further include a bonding layer, and at least two adjacent and stacked layer structures are bonded together by the bonding layer. For example, a bonding layer is provided between any two adjacent layers of the above-mentioned sequentially stacked heat absorption expansion layer 12, the phase change thermal insulation layer 11, and the heat absorption expansion layer 12.

[0115] Furthermore, the material of each of the above-mentioned adhesive layers is independently a silicone adhesive layer, and the thickness is independently 0.04~0.06mm. The silicone adhesive layer is resistant to high temperatures and has high structural strength. The peeling force of the prepared composite thermal insulation pad is greater than 10N / cm. The peeling force can be measured by pulling the two sides of the composite thermal insulation pad with a tensile gauge, and applying a force perpendicular to the composite thermal insulation pad at 90° to the two sides of the composite thermal insulation pad. The tensile gauge will display the magnitude of the pulling force when the composite thermal insulation pad is peeled off, and the peeling force can be obtained based on the magnitude of the pulling force.

[0116] In some embodiments, the composite thermal insulation pad 10 further includes a release adhesive layer (not shown). The release adhesive layer includes a release film and an adhesive layer disposed on the release film, and the adhesive layer is disposed on at least one side of the outer surface of the body of the composite thermal insulation pad 10, such as two opposite sides in the thickness direction. In this way, when the composite thermal insulation pad 10 needs to be fixed at a target position, such as a target battery cell, the release film on the surface of the release adhesive layer on the composite thermal insulation pad 10 is removed, and it is simply and conveniently fixed to the target position by bonding with the adhesive layer, which can play the role of fixing the composite thermal insulation pad 10.

[0117] As an example, the above-mentioned release adhesive layer is provided on the outer surfaces of the two opposite sides of the outer surface thickness direction of the body of the composite thermal insulation pad 10. When in use, the composite thermal insulation pad 10 can be bonded and fixed to two objects respectively through the release adhesive layers on both sides, for example, bonded and fixed to two adjacent battery cells respectively, so that the composite thermal insulation pad 10 is arranged between the two adjacent battery cells.

[0118] See also Fig. 9 In some embodiments, the composite thermal insulation pad 10 further includes a first packaging frame 161 and a second packaging frame 162. The first packaging frame 161 and the second packaging frame 162 cooperate to fix the phase change thermal insulation layer 11 and the heat absorption expansion layer 12.

[0119] Further, the first packaging frame 161 and the second packaging frame 162 are each independently a rubber frame or a silicone frame, which has good flexibility and can absorb the expansion force caused by the expansion of the battery. In other words, the material of the first packaging frame 161 and the second packaging frame 162 is each independently rubber or silicone. Further, the first packaging frame 161 and the second packaging frame 162 are each independently a mouth-shaped frame, such as a mouth-shaped silicone frame.

[0120] Furthermore, the first packaging frame 161 has a first limiting groove (not shown), and the second packaging frame 162 has a second limiting groove (not shown), and the phase change thermal insulation layer 11 and the heat absorption expansion layer 12 are limited in the limiting space formed by the first limiting groove and the second limiting groove. The first limiting groove and the second limiting groove can be limited in the thickness direction and radial direction of the composite thermal insulation pad 10, thereby improving the structural stability of the composite thermal insulation pad 10.

[0121] Furthermore, in Fig. 9 In the specific example shown, the composite thermal insulation pad body encapsulated by the encapsulation frame is Figure 2 The composite thermal insulation pad shown; it can be understood that in other examples, any one of the above-mentioned composite thermal insulation pads can be used.

[0122] The radial direction of the composite thermal insulation pad 10 refers to the direction from the center of the composite thermal insulation pad 10 to the edge of the composite thermal insulation pad 10 .

[0123] It can be understood that in some embodiments, the film layers of the composite thermal insulation pad 10 can be connected by the above-mentioned adhesive layer instead of the above-mentioned packaging frame, or by the above-mentioned packaging frame instead of the above-mentioned adhesive layer, or by both the above-mentioned adhesive layer and the packaging frame, or by neither, for example, the outer thermal insulation layer can be directly formed on the corresponding surface in the form of a coating.

[0124] See also Fig.10 and Fig.11 Another embodiment of the present application further provides a battery 30, which includes any of the above-mentioned composite thermal insulation pads 10.

[0125] Further, the battery 30 further includes a plurality of battery cells 20, and the composite thermal insulation pad 10 is disposed between at least two adjacent battery cells 20. Optionally, a composite thermal insulation pad 10 is disposed between any two adjacent battery cells 20. Further, a composite thermal insulation pad 10 is disposed between the large surfaces of at least two adjacent battery cells 20.

[0126] It is understandable that the above-mentioned composite thermal insulation pad 10 may also be provided between the battery cell 20 and the inner wall of the battery 30 shell.

[0127] It is understood that the shape of the battery cell 20 includes but is not limited to a square or a cylinder. The composite thermal insulation pad 10 can be arranged in a manner that is consistent with the shape of the battery cell 20 .

[0128] In some of the embodiments, the battery cell 20 is square, and the composite thermal insulation pad 10 is disposed on a side surface of the battery cell 20 with a larger area to increase its contact area and improve the thermal insulation performance.

[0129] Furthermore, the composite thermal insulation pad 10 is disposed between the large surfaces of two adjacent battery cells 20 .

[0130] In this application, unless otherwise specified, "battery cell 20" refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and further, generally speaking, at least includes a positive electrode sheet, a negative electrode sheet and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet.

[0131] It is understandable that after the multiple battery cells 20 are connected to each other and arranged in a certain order, they can be directly placed in the box to assemble into a battery 30. Alternatively, multiple battery cells 20 can be first formed into a battery module, and then multiple battery modules are connected to each other to form a whole, and finally the whole battery module is placed in the box to form a battery 30.

[0132] Generally, the battery cell 20 includes a shell, a cover plate and an electrode assembly. The electrode assembly is accommodated in the shell, and the cover plate is sealed at the opening.

[0133] For example, Fig.12 The battery cell 20 is a square structure as an example. The battery cell 20 includes a housing 21, a cover plate 23 and an electrode assembly 22. The electrode assembly 22 is accommodated in the housing 21, and the cover plate 23 is sealed at the opening. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet and a separator. The positive electrode sheet, the negative electrode sheet and the separator can be formed by a winding process or a lamination process.

[0134] Furthermore, the electrode assembly 22 also includes an electrolyte, such as an electrolyte. The electrolyte is infiltrated in the electrode assembly 22. The number of electrode assemblies 22 included in the battery cell 20 can be one or more, and those skilled in the art can select according to specific actual needs.

[0135] Furthermore, one or both ends of the housing 21 are provided with an opening.

[0136] Further, the housing 21 is a rectangular housing, and the opening direction of the housing 21 is the height direction of the housing 21. Further, both ends of the housing 21 are provided with openings, and the two openings are arranged oppositely along the height direction of the housing 21. Further as a non-limiting example, the height of the housing 21 is 80 mm to 210 mm; further as a non-limiting example, the length of the housing 21 is 90 mm to 240 mm; further as a non-limiting example, the width of the housing 21 is 20 mm to 80 mm.

[0137] Furthermore, the battery cell 20 and the shell 21 are rectangular shells, and the composite insulation pad 10 is arranged on the larger side of the battery cell 20, which is perpendicular to the above-mentioned width direction, that is, the side formed by the two sides of the above-mentioned length direction and height direction.

[0138] As a further non-limiting example, the wall thickness of the housing 21 is 0.5 mm to 0.8 mm.

[0139] Furthermore, the housing 21 is an aluminum alloy housing; for example, a three-series aluminum alloy housing or a five-series aluminum alloy housing.

[0140] Furthermore, the aluminum alloy of the three-series aluminum alloy shell includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

[0141] Furthermore, the aluminum alloy of the fifth series aluminum alloy shell includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0142] Another embodiment of the present application further provides an electrical device, including the above-mentioned battery provided in the present application. The above-mentioned battery can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto. Among them, the mobile device may be, for example, a mobile phone, a laptop computer, etc.; the electric vehicle may be, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc., but are not limited thereto.

[0143] As an electrical device, a battery cell, a battery module or a battery pack can be selected as its power source according to its usage requirements.

[0144] Fig.13 The power consumption device 40 is taken as an example. The power consumption device 40 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device's requirements for high power and high energy density of secondary batteries, a battery pack or a battery module can be used as a power source.

[0145] As another example, the device may be a mobile phone, a tablet computer, a notebook computer, etc. The device is usually required to be light and thin, and a battery cell may be used as a power source.

[0146] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0147] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A composite thermal insulation pad, characterized in that: include: A phase-change heat-insulating layer, comprising a heat-insulating substrate and a phase-change material filled in pores of the heat-insulating substrate; and The heat-absorbing expansion layer is arranged on at least one side of the outer peripheral side of the phase-change heat-insulating layer and / or inside the phase-change heat-insulating layer.

2. The composite thermal insulation pad according to claim 1, characterized in that: The heat-absorbing expansion layer is disposed inside the heat-insulating substrate.

3. The composite thermal insulation pad according to claim 2, characterized in that: The projection of the heat-absorbing expansion layer on the thermal insulation substrate in the thickness direction of the composite thermal insulation pad does not exceed the thermal insulation substrate.

4. The composite thermal insulation pad according to claim 3, characterized in that: The projected area of ​​the heat-absorbing expansion layer on the thermal insulation substrate in the thickness direction of the composite thermal insulation pad is 90% to 100% of the area of ​​the thermal insulation substrate.

5. The composite thermal insulation pad according to claim 2, characterized in that: The composite thermal insulation pad also includes a first outer thermal insulation layer, which is arranged on at least one side of the outer peripheral side of the phase change thermal insulation layer along the thickness direction.

6. The composite thermal insulation pad according to claim 1, characterized in that: There are at least two heat-absorbing expansion layers, and at least one heat-absorbing expansion layer is respectively disposed on both sides of the outer peripheral side of the phase-change heat-insulating layer in the thickness direction.

7. The composite thermal insulation pad according to claim 6, characterized in that: The composite thermal insulation pad also includes a second outer thermal insulation layer, which is arranged on a side of the heat absorption and expansion layer away from the phase change thermal insulation layer.

8. The composite thermal insulation pad according to any one of claims 1 to 7, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The heat-absorbing and expanding layer is an expanded graphite layer; (2) The thermal insulation substrate is a ceramic material thermal insulation substrate.

9. The composite thermal insulation pad according to any one of claims 1 to 7, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The thickness of the heat-absorbing expansion layer is 0.5 mm to 5 mm; (2) The thickness of the phase change thermal insulation layer is 0.5 mm to 5 mm.

10. The composite thermal insulation pad according to any one of claims 1 to 7, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The composite thermal insulation pad further includes a first packaging layer, which is disposed on the outer surface of the heat absorption and expansion layer and encapsulates the heat absorption and expansion layer; (2) The composite thermal insulation pad also includes a second encapsulation layer, which is arranged on the outer surface of the phase change thermal insulation layer and encapsulates the phase change thermal insulation layer.

11. The composite thermal insulation pad according to claim 10, characterized in that: The composite thermal insulation pad meets at least one of the following conditions: (1) The first packaging layer is an aluminum-plastic film or a polymer packaging film; (2) The second packaging layer is an aluminum-plastic film or a polymer packaging film; (3) The thickness of the first encapsulation layer is 0.1 mm to 0.3 mm; (4) The thickness of the second packaging layer is 0.1 mm to 0.3 mm.

12. The composite thermal insulation pad according to any one of claims 1 to 7 and 11, characterized in that: The composite thermal insulation pad also includes a first packaging frame and a second packaging frame, and the first packaging frame cooperates with the second packaging frame to fix the phase change thermal insulation layer and the heat absorption expansion layer.

13. A battery, characterized in that: Comprising the composite thermal insulation pad as described in any one of claims 1 to 12.

14. The battery according to claim 13, characterized in that The battery further comprises a plurality of battery cells, and the composite heat insulation pad is arranged between at least two adjacent battery cells.

15. The battery according to any one of claims 13 to 14, characterized in that: The composite heat-insulating pad is arranged between the large surfaces of at least two adjacent battery cells.

16. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 13 to 15.

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